It's an interesting question.....how many people did the Dead turn on to these "inaccessible modernist" music styles? Are there hordes of people who became fans of drum solos & drumming bands because of seeing the Dead? Are there untold millions who started listening to free jazz and abstract noise because they went to some Dead shows?
Or, maybe there are noise-freaks who could never stand a country tune until they heard the Dead do some? I don't know; depends what you call inaccessible....

The "feedback" is my favorite part of many a show. Funny thing is, I always considered it "normal" music....just like doing whole sets of songs seguing into each other with transitional jamming, once I heard the Dead doing it, not only did it not seem unusual, but I had to wonder why more bands weren't doing it. And afterwards it became hard to take "pop" bands that do the same short songs every night.

The Dead mixed a whole bunch of different styles into their shows....over time, more styles kept getting put into the mix. Some of us might like all of it; others prefer one stage of it, or just a few types of the songs they did. It didn't seem to me like a matter of getting introduced to 'strange' new music - after all, since '66 the Beatles (and others) had been showing how much variety a rock band could offer, from the simple tunes to the strange freakouts. An early Dead staple like Viola Lee Blues is very much in the spirit of Sgt Pepper, that kind of blending was "in the air" then. But most bands don't have the range to give us that variety....